git.oblomov.eu Git - linux-2.6/blob - fs/ecryptfs/mmap.c

   1 /**
   2  * eCryptfs: Linux filesystem encryption layer
   3  * This is where eCryptfs coordinates the symmetric encryption and
   4  * decryption of the file data as it passes between the lower
   5  * encrypted file and the upper decrypted file.
   6  *
   7  * Copyright (C) 1997-2003 Erez Zadok
   8  * Copyright (C) 2001-2003 Stony Brook University
   9  * Copyright (C) 2004-2006 International Business Machines Corp.
  10  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  * General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  25  * 02111-1307, USA.
  26  */
  27
  28 #include <linux/pagemap.h>
  29 #include <linux/writeback.h>
  30 #include <linux/page-flags.h>
  31 #include <linux/mount.h>
  32 #include <linux/file.h>
  33 #include <linux/crypto.h>
  34 #include <linux/scatterlist.h>
  35 #include "ecryptfs_kernel.h"
  36
  37 struct kmem_cache *ecryptfs_lower_page_cache;
  38
  39 /**
  40  * ecryptfs_get1page
  41  *
  42  * Get one page from cache or lower f/s, return error otherwise.
  43  *
  44  * Returns unlocked and up-to-date page (if ok), with increased
  45  * refcnt.
  46  */
  47 static struct page *ecryptfs_get1page(struct file *file, int index)
  48 {
  49         struct page *page;
  50         struct dentry *dentry;
  51         struct inode *inode;
  52         struct address_space *mapping;
  53
  54         dentry = file->f_path.dentry;
  55         inode = dentry->d_inode;
  56         mapping = inode->i_mapping;
  57         page = read_cache_page(mapping, index,
  58                                (filler_t *)mapping->a_ops->readpage,
  59                                (void *)file);
  60         if (IS_ERR(page))
  61                 goto out;
  62         wait_on_page_locked(page);
  63 out:
  64         return page;
  65 }
  66
  67 static
  68 int write_zeros(struct file *file, pgoff_t index, int start, int num_zeros);
  69
  70 /**
  71  * ecryptfs_fill_zeros
  72  * @file: The ecryptfs file
  73  * @new_length: The new length of the data in the underlying file;
  74  *              everything between the prior end of the file and the
  75  *              new end of the file will be filled with zero's.
  76  *              new_length must be greater than  current length
  77  *
  78  * Function for handling lseek-ing past the end of the file.
  79  *
  80  * This function does not support shrinking, only growing a file.
  81  *
  82  * Returns zero on success; non-zero otherwise.
  83  */
  84 int ecryptfs_fill_zeros(struct file *file, loff_t new_length)
  85 {
  86         int rc = 0;
  87         struct dentry *dentry = file->f_path.dentry;
  88         struct inode *inode = dentry->d_inode;
  89         pgoff_t old_end_page_index = 0;
  90         pgoff_t index = old_end_page_index;
  91         int old_end_pos_in_page = -1;
  92         pgoff_t new_end_page_index;
  93         int new_end_pos_in_page;
  94         loff_t cur_length = i_size_read(inode);
  95
  96         if (cur_length != 0) {
  97                 index = old_end_page_index =
  98                     ((cur_length - 1) >> PAGE_CACHE_SHIFT);
  99                 old_end_pos_in_page = ((cur_length - 1) & ~PAGE_CACHE_MASK);
 100         }
 101         new_end_page_index = ((new_length - 1) >> PAGE_CACHE_SHIFT);
 102         new_end_pos_in_page = ((new_length - 1) & ~PAGE_CACHE_MASK);
 103         ecryptfs_printk(KERN_DEBUG, "old_end_page_index = [0x%.16x]; "
 104                         "old_end_pos_in_page = [%d]; "
 105                         "new_end_page_index = [0x%.16x]; "
 106                         "new_end_pos_in_page = [%d]\n",
 107                         old_end_page_index, old_end_pos_in_page,
 108                         new_end_page_index, new_end_pos_in_page);
 109         if (old_end_page_index == new_end_page_index) {
 110                 /* Start and end are in the same page; we just need to
 111                  * set a portion of the existing page to zero's */
 112                 rc = write_zeros(file, index, (old_end_pos_in_page + 1),
 113                                  (new_end_pos_in_page - old_end_pos_in_page));
 114                 if (rc)
 115                         ecryptfs_printk(KERN_ERR, "write_zeros(file=[%p], "
 116                                         "index=[0x%.16x], "
 117                                         "old_end_pos_in_page=[d], "
 118                                         "(PAGE_CACHE_SIZE - new_end_pos_in_page"
 119                                         "=[%d]"
 120                                         ")=[d]) returned [%d]\n", file, index,
 121                                         old_end_pos_in_page,
 122                                         new_end_pos_in_page,
 123                                         (PAGE_CACHE_SIZE - new_end_pos_in_page),
 124                                         rc);
 125                 goto out;
 126         }
 127         /* Fill the remainder of the previous last page with zeros */
 128         rc = write_zeros(file, index, (old_end_pos_in_page + 1),
 129                          ((PAGE_CACHE_SIZE - 1) - old_end_pos_in_page));
 130         if (rc) {
 131                 ecryptfs_printk(KERN_ERR, "write_zeros(file=[%p], "
 132                                 "index=[0x%.16x], old_end_pos_in_page=[d], "
 133                                 "(PAGE_CACHE_SIZE - old_end_pos_in_page)=[d]) "
 134                                 "returned [%d]\n", file, index,
 135                                 old_end_pos_in_page,
 136                                 (PAGE_CACHE_SIZE - old_end_pos_in_page), rc);
 137                 goto out;
 138         }
 139         index++;
 140         while (index < new_end_page_index) {
 141                 /* Fill all intermediate pages with zeros */
 142                 rc = write_zeros(file, index, 0, PAGE_CACHE_SIZE);
 143                 if (rc) {
 144                         ecryptfs_printk(KERN_ERR, "write_zeros(file=[%p], "
 145                                         "index=[0x%.16x], "
 146                                         "old_end_pos_in_page=[d], "
 147                                         "(PAGE_CACHE_SIZE - new_end_pos_in_page"
 148                                         "=[%d]"
 149                                         ")=[d]) returned [%d]\n", file, index,
 150                                         old_end_pos_in_page,
 151                                         new_end_pos_in_page,
 152                                         (PAGE_CACHE_SIZE - new_end_pos_in_page),
 153                                         rc);
 154                         goto out;
 155                 }
 156                 index++;
 157         }
 158         /* Fill the portion at the beginning of the last new page with
 159          * zero's */
 160         rc = write_zeros(file, index, 0, (new_end_pos_in_page + 1));
 161         if (rc) {
 162                 ecryptfs_printk(KERN_ERR, "write_zeros(file="
 163                                 "[%p], index=[0x%.16x], 0, "
 164                                 "new_end_pos_in_page=[%d]"
 165                                 "returned [%d]\n", file, index,
 166                                 new_end_pos_in_page, rc);
 167                 goto out;
 168         }
 169 out:
 170         return rc;
 171 }
 172
 173 /**
 174  * ecryptfs_writepage
 175  * @page: Page that is locked before this call is made
 176  *
 177  * Returns zero on success; non-zero otherwise
 178  */
 179 static int ecryptfs_writepage(struct page *page, struct writeback_control *wbc)
 180 {
 181         struct ecryptfs_page_crypt_context ctx;
 182         int rc;
 183
 184         ctx.page = page;
 185         ctx.mode = ECRYPTFS_WRITEPAGE_MODE;
 186         ctx.param.wbc = wbc;
 187         rc = ecryptfs_encrypt_page(&ctx);
 188         if (rc) {
 189                 ecryptfs_printk(KERN_WARNING, "Error encrypting "
 190                                 "page (upper index [0x%.16x])\n", page->index);
 191                 ClearPageUptodate(page);
 192                 goto out;
 193         }
 194         SetPageUptodate(page);
 195         unlock_page(page);
 196 out:
 197         return rc;
 198 }
 199
 200 /**
 201  * Reads the data from the lower file file at index lower_page_index
 202  * and copies that data into page.
 203  *
 204  * @param page  Page to fill
 205  * @param lower_page_index Index of the page in the lower file to get
 206  */
 207 int ecryptfs_do_readpage(struct file *file, struct page *page,
 208                          pgoff_t lower_page_index)
 209 {
 210         int rc;
 211         struct dentry *dentry;
 212         struct file *lower_file;
 213         struct dentry *lower_dentry;
 214         struct inode *inode;
 215         struct inode *lower_inode;
 216         char *page_data;
 217         struct page *lower_page = NULL;
 218         char *lower_page_data;
 219         const struct address_space_operations *lower_a_ops;
 220
 221         dentry = file->f_path.dentry;
 222         lower_file = ecryptfs_file_to_lower(file);
 223         lower_dentry = ecryptfs_dentry_to_lower(dentry);
 224         inode = dentry->d_inode;
 225         lower_inode = ecryptfs_inode_to_lower(inode);
 226         lower_a_ops = lower_inode->i_mapping->a_ops;
 227         lower_page = read_cache_page(lower_inode->i_mapping, lower_page_index,
 228                                      (filler_t *)lower_a_ops->readpage,
 229                                      (void *)lower_file);
 230         if (IS_ERR(lower_page)) {
 231                 rc = PTR_ERR(lower_page);
 232                 lower_page = NULL;
 233                 ecryptfs_printk(KERN_ERR, "Error reading from page cache\n");
 234                 goto out;
 235         }
 236         wait_on_page_locked(lower_page);
 237         page_data = (char *)kmap(page);
 238         if (!page_data) {
 239                 rc = -ENOMEM;
 240                 ecryptfs_printk(KERN_ERR, "Error mapping page\n");
 241                 goto out;
 242         }
 243         lower_page_data = (char *)kmap(lower_page);
 244         if (!lower_page_data) {
 245                 rc = -ENOMEM;
 246                 ecryptfs_printk(KERN_ERR, "Error mapping page\n");
 247                 kunmap(page);
 248                 goto out;
 249         }
 250         memcpy(page_data, lower_page_data, PAGE_CACHE_SIZE);
 251         kunmap(lower_page);
 252         kunmap(page);
 253         rc = 0;
 254 out:
 255         if (likely(lower_page))
 256                 page_cache_release(lower_page);
 257         if (rc == 0)
 258                 SetPageUptodate(page);
 259         else
 260                 ClearPageUptodate(page);
 261         return rc;
 262 }
 263
 264 /**
 265  * ecryptfs_readpage
 266  * @file: This is an ecryptfs file
 267  * @page: ecryptfs associated page to stick the read data into
 268  *
 269  * Read in a page, decrypting if necessary.
 270  *
 271  * Returns zero on success; non-zero on error.
 272  */
 273 static int ecryptfs_readpage(struct file *file, struct page *page)
 274 {
 275         int rc = 0;
 276         struct ecryptfs_crypt_stat *crypt_stat;
 277
 278         BUG_ON(!(file && file->f_path.dentry && file->f_path.dentry->d_inode));
 279         crypt_stat = &ecryptfs_inode_to_private(file->f_path.dentry->d_inode)
 280                         ->crypt_stat;
 281         if (!crypt_stat
 282             || !ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED)
 283             || ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE)) {
 284                 ecryptfs_printk(KERN_DEBUG,
 285                                 "Passing through unencrypted page\n");
 286                 rc = ecryptfs_do_readpage(file, page, page->index);
 287                 if (rc) {
 288                         ecryptfs_printk(KERN_ERR, "Error reading page; rc = "
 289                                         "[%d]\n", rc);
 290                         goto out;
 291                 }
 292         } else {
 293                 rc = ecryptfs_decrypt_page(file, page);
 294                 if (rc) {
 295
 296                         ecryptfs_printk(KERN_ERR, "Error decrypting page; "
 297                                         "rc = [%d]\n", rc);
 298                         goto out;
 299                 }
 300         }
 301         SetPageUptodate(page);
 302 out:
 303         if (rc)
 304                 ClearPageUptodate(page);
 305         ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n",
 306                         page->index);
 307         unlock_page(page);
 308         return rc;
 309 }
 310
 311 static int fill_zeros_to_end_of_page(struct page *page, unsigned int to)
 312 {
 313         struct inode *inode = page->mapping->host;
 314         int end_byte_in_page;
 315         int rc = 0;
 316         char *page_virt;
 317
 318         if ((i_size_read(inode) / PAGE_CACHE_SIZE) == page->index) {
 319                 end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE;
 320                 if (to > end_byte_in_page)
 321                         end_byte_in_page = to;
 322                 page_virt = kmap(page);
 323                 if (!page_virt) {
 324                         rc = -ENOMEM;
 325                         ecryptfs_printk(KERN_WARNING,
 326                                         "Could not map page\n");
 327                         goto out;
 328                 }
 329                 memset((page_virt + end_byte_in_page), 0,
 330                        (PAGE_CACHE_SIZE - end_byte_in_page));
 331                 kunmap(page);
 332         }
 333 out:
 334         return rc;
 335 }
 336
 337 static int ecryptfs_prepare_write(struct file *file, struct page *page,
 338                                   unsigned from, unsigned to)
 339 {
 340         int rc = 0;
 341
 342         kmap(page);
 343         if (from == 0 && to == PAGE_CACHE_SIZE)
 344                 goto out;       /* If we are writing a full page, it will be
 345                                    up to date. */
 346         if (!PageUptodate(page))
 347                 rc = ecryptfs_do_readpage(file, page, page->index);
 348 out:
 349         return rc;
 350 }
 351
 352 int ecryptfs_grab_and_map_lower_page(struct page **lower_page,
 353                                      char **lower_virt,
 354                                      struct inode *lower_inode,
 355                                      unsigned long lower_page_index)
 356 {
 357         int rc = 0;
 358
 359         (*lower_page) = grab_cache_page(lower_inode->i_mapping,
 360                                         lower_page_index);
 361         if (!(*lower_page)) {
 362                 ecryptfs_printk(KERN_ERR, "grab_cache_page for "
 363                                 "lower_page_index = [0x%.16x] failed\n",
 364                                 lower_page_index);
 365                 rc = -EINVAL;
 366                 goto out;
 367         }
 368         if (lower_virt)
 369                 (*lower_virt) = kmap((*lower_page));
 370         else
 371                 kmap((*lower_page));
 372 out:
 373         return rc;
 374 }
 375
 376 int ecryptfs_writepage_and_release_lower_page(struct page *lower_page,
 377                                               struct inode *lower_inode,
 378                                               struct writeback_control *wbc)
 379 {
 380         int rc = 0;
 381
 382         rc = lower_inode->i_mapping->a_ops->writepage(lower_page, wbc);
 383         if (rc) {
 384                 ecryptfs_printk(KERN_ERR, "Error calling lower writepage(); "
 385                                 "rc = [%d]\n", rc);
 386                 goto out;
 387         }
 388         lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
 389         page_cache_release(lower_page);
 390 out:
 391         return rc;
 392 }
 393
 394 static void ecryptfs_unmap_and_release_lower_page(struct page *lower_page)
 395 {
 396         kunmap(lower_page);
 397         ecryptfs_printk(KERN_DEBUG, "Unlocking lower page with index = "
 398                         "[0x%.16x]\n", lower_page->index);
 399         unlock_page(lower_page);
 400         page_cache_release(lower_page);
 401 }
 402
 403 /**
 404  * ecryptfs_write_inode_size_to_header
 405  *
 406  * Writes the lower file size to the first 8 bytes of the header.
 407  *
 408  * Returns zero on success; non-zero on error.
 409  */
 410 int
 411 ecryptfs_write_inode_size_to_header(struct file *lower_file,
 412                                     struct inode *lower_inode,
 413                                     struct inode *inode)
 414 {
 415         int rc = 0;
 416         struct page *header_page;
 417         char *header_virt;
 418         const struct address_space_operations *lower_a_ops;
 419         u64 file_size;
 420
 421         rc = ecryptfs_grab_and_map_lower_page(&header_page, &header_virt,
 422                                               lower_inode, 0);
 423         if (rc) {
 424                 ecryptfs_printk(KERN_ERR, "grab_cache_page for header page "
 425                                 "failed\n");
 426                 goto out;
 427         }
 428         lower_a_ops = lower_inode->i_mapping->a_ops;
 429         rc = lower_a_ops->prepare_write(lower_file, header_page, 0, 8);
 430         file_size = (u64)i_size_read(inode);
 431         ecryptfs_printk(KERN_DEBUG, "Writing size: [0x%.16x]\n", file_size);
 432         file_size = cpu_to_be64(file_size);
 433         memcpy(header_virt, &file_size, sizeof(u64));
 434         rc = lower_a_ops->commit_write(lower_file, header_page, 0, 8);
 435         if (rc < 0)
 436                 ecryptfs_printk(KERN_ERR, "Error commiting header page "
 437                                 "write\n");
 438         ecryptfs_unmap_and_release_lower_page(header_page);
 439         lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
 440         mark_inode_dirty_sync(inode);
 441 out:
 442         return rc;
 443 }
 444
 445 int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode,
 446                             struct file *lower_file,
 447                             unsigned long lower_page_index, int byte_offset,
 448                             int region_bytes)
 449 {
 450         int rc = 0;
 451
 452         rc = ecryptfs_grab_and_map_lower_page(lower_page, NULL, lower_inode,
 453                                               lower_page_index);
 454         if (rc) {
 455                 ecryptfs_printk(KERN_ERR, "Error attempting to grab and map "
 456                                 "lower page with index [0x%.16x]\n",
 457                                 lower_page_index);
 458                 goto out;
 459         }
 460         rc = lower_inode->i_mapping->a_ops->prepare_write(lower_file,
 461                                                           (*lower_page),
 462                                                           byte_offset,
 463                                                           region_bytes);
 464         if (rc) {
 465                 ecryptfs_printk(KERN_ERR, "prepare_write for "
 466                                 "lower_page_index = [0x%.16x] failed; rc = "
 467                                 "[%d]\n", lower_page_index, rc);
 468         }
 469 out:
 470         if (rc && (*lower_page)) {
 471                 ecryptfs_unmap_and_release_lower_page(*lower_page);
 472                 (*lower_page) = NULL;
 473         }
 474         return rc;
 475 }
 476
 477 /**
 478  * ecryptfs_commit_lower_page
 479  *
 480  * Returns zero on success; non-zero on error
 481  */
 482 int
 483 ecryptfs_commit_lower_page(struct page *lower_page, struct inode *lower_inode,
 484                            struct file *lower_file, int byte_offset,
 485                            int region_size)
 486 {
 487         int rc = 0;
 488
 489         rc = lower_inode->i_mapping->a_ops->commit_write(
 490                 lower_file, lower_page, byte_offset, region_size);
 491         if (rc < 0) {
 492                 ecryptfs_printk(KERN_ERR,
 493                                 "Error committing write; rc = [%d]\n", rc);
 494         } else
 495                 rc = 0;
 496         ecryptfs_unmap_and_release_lower_page(lower_page);
 497         return rc;
 498 }
 499
 500 /**
 501  * ecryptfs_copy_page_to_lower
 502  *
 503  * Used for plaintext pass-through; no page index interpolation
 504  * required.
 505  */
 506 int ecryptfs_copy_page_to_lower(struct page *page, struct inode *lower_inode,
 507                                 struct file *lower_file)
 508 {
 509         int rc = 0;
 510         struct page *lower_page;
 511
 512         rc = ecryptfs_get_lower_page(&lower_page, lower_inode, lower_file,
 513                                      page->index, 0, PAGE_CACHE_SIZE);
 514         if (rc) {
 515                 ecryptfs_printk(KERN_ERR, "Error attempting to get page "
 516                                 "at index [0x%.16x]\n", page->index);
 517                 goto out;
 518         }
 519         /* TODO: aops */
 520         memcpy((char *)page_address(lower_page), page_address(page),
 521                PAGE_CACHE_SIZE);
 522         rc = ecryptfs_commit_lower_page(lower_page, lower_inode, lower_file,
 523                                         0, PAGE_CACHE_SIZE);
 524         if (rc)
 525                 ecryptfs_printk(KERN_ERR, "Error attempting to commit page "
 526                                 "at index [0x%.16x]\n", page->index);
 527 out:
 528         return rc;
 529 }
 530
 531 static int
 532 process_new_file(struct ecryptfs_crypt_stat *crypt_stat,
 533                  struct file *file, struct inode *inode)
 534 {
 535         struct page *header_page;
 536         const struct address_space_operations *lower_a_ops;
 537         struct inode *lower_inode;
 538         struct file *lower_file;
 539         char *header_virt;
 540         int rc = 0;
 541         int current_header_page = 0;
 542         int header_pages;
 543         int more_header_data_to_be_written = 1;
 544
 545         lower_inode = ecryptfs_inode_to_lower(inode);
 546         lower_file = ecryptfs_file_to_lower(file);
 547         lower_a_ops = lower_inode->i_mapping->a_ops;
 548         header_pages = ((crypt_stat->header_extent_size
 549                          * crypt_stat->num_header_extents_at_front)
 550                         / PAGE_CACHE_SIZE);
 551         BUG_ON(header_pages < 1);
 552         while (current_header_page < header_pages) {
 553                 rc = ecryptfs_grab_and_map_lower_page(&header_page,
 554                                                       &header_virt,
 555                                                       lower_inode,
 556                                                       current_header_page);
 557                 if (rc) {
 558                         ecryptfs_printk(KERN_ERR, "grab_cache_page for "
 559                                         "header page [%d] failed; rc = [%d]\n",
 560                                         current_header_page, rc);
 561                         goto out;
 562                 }
 563                 rc = lower_a_ops->prepare_write(lower_file, header_page, 0,
 564                                                 PAGE_CACHE_SIZE);
 565                 if (rc) {
 566                         ecryptfs_printk(KERN_ERR, "Error preparing to write "
 567                                         "header page out; rc = [%d]\n", rc);
 568                         goto out;
 569                 }
 570                 memset(header_virt, 0, PAGE_CACHE_SIZE);
 571                 if (more_header_data_to_be_written) {
 572                         rc = ecryptfs_write_headers_virt(header_virt,
 573                                                          crypt_stat,
 574                                                          file->f_dentry);
 575                         if (rc) {
 576                                 ecryptfs_printk(KERN_WARNING, "Error "
 577                                                 "generating header; rc = "
 578                                                 "[%d]\n", rc);
 579                                 rc = -EIO;
 580                                 memset(header_virt, 0, PAGE_CACHE_SIZE);
 581                                 ecryptfs_unmap_and_release_lower_page(
 582                                         header_page);
 583                                 goto out;
 584                         }
 585                         if (current_header_page == 0)
 586                                 memset(header_virt, 0, 8);
 587                         more_header_data_to_be_written = 0;
 588                 }
 589                 rc = lower_a_ops->commit_write(lower_file, header_page, 0,
 590                                                PAGE_CACHE_SIZE);
 591                 ecryptfs_unmap_and_release_lower_page(header_page);
 592                 if (rc < 0) {
 593                         ecryptfs_printk(KERN_ERR,
 594                                         "Error commiting header page write; "
 595                                         "rc = [%d]\n", rc);
 596                         break;
 597                 }
 598                 current_header_page++;
 599         }
 600         if (rc >= 0) {
 601                 rc = 0;
 602                 ecryptfs_printk(KERN_DEBUG, "lower_inode->i_blocks = "
 603                                 "[0x%.16x]\n", lower_inode->i_blocks);
 604                 i_size_write(inode, 0);
 605                 lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
 606                 mark_inode_dirty_sync(inode);
 607         }
 608         ecryptfs_printk(KERN_DEBUG, "Clearing ECRYPTFS_NEW_FILE flag in "
 609                         "crypt_stat at memory location [%p]\n", crypt_stat);
 610         ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE);
 611 out:
 612         return rc;
 613 }
 614
 615 /**
 616  * ecryptfs_commit_write
 617  * @file: The eCryptfs file object
 618  * @page: The eCryptfs page
 619  * @from: Ignored (we rotate the page IV on each write)
 620  * @to: Ignored
 621  *
 622  * This is where we encrypt the data and pass the encrypted data to
 623  * the lower filesystem.  In OpenPGP-compatible mode, we operate on
 624  * entire underlying packets.
 625  */
 626 static int ecryptfs_commit_write(struct file *file, struct page *page,
 627                                  unsigned from, unsigned to)
 628 {
 629         struct ecryptfs_page_crypt_context ctx;
 630         loff_t pos;
 631         struct inode *inode;
 632         struct inode *lower_inode;
 633         struct file *lower_file;
 634         struct ecryptfs_crypt_stat *crypt_stat;
 635         int rc;
 636
 637         inode = page->mapping->host;
 638         lower_inode = ecryptfs_inode_to_lower(inode);
 639         lower_file = ecryptfs_file_to_lower(file);
 640         mutex_lock(&lower_inode->i_mutex);
 641         crypt_stat = &ecryptfs_inode_to_private(file->f_path.dentry->d_inode)
 642                                 ->crypt_stat;
 643         if (ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE)) {
 644                 ecryptfs_printk(KERN_DEBUG, "ECRYPTFS_NEW_FILE flag set in "
 645                         "crypt_stat at memory location [%p]\n", crypt_stat);
 646                 rc = process_new_file(crypt_stat, file, inode);
 647                 if (rc) {
 648                         ecryptfs_printk(KERN_ERR, "Error processing new "
 649                                         "file; rc = [%d]\n", rc);
 650                         goto out;
 651                 }
 652         } else
 653                 ecryptfs_printk(KERN_DEBUG, "Not a new file\n");
 654         ecryptfs_printk(KERN_DEBUG, "Calling fill_zeros_to_end_of_page"
 655                         "(page w/ index = [0x%.16x], to = [%d])\n", page->index,
 656                         to);
 657         rc = fill_zeros_to_end_of_page(page, to);
 658         if (rc) {
 659                 ecryptfs_printk(KERN_WARNING, "Error attempting to fill "
 660                                 "zeros in page with index = [0x%.16x]\n",
 661                                 page->index);
 662                 goto out;
 663         }
 664         ctx.page = page;
 665         ctx.mode = ECRYPTFS_PREPARE_COMMIT_MODE;
 666         ctx.param.lower_file = lower_file;
 667         rc = ecryptfs_encrypt_page(&ctx);
 668         if (rc) {
 669                 ecryptfs_printk(KERN_WARNING, "Error encrypting page (upper "
 670                                 "index [0x%.16x])\n", page->index);
 671                 goto out;
 672         }
 673         rc = 0;
 674         inode->i_blocks = lower_inode->i_blocks;
 675         pos = (page->index << PAGE_CACHE_SHIFT) + to;
 676         if (pos > i_size_read(inode)) {
 677                 i_size_write(inode, pos);
 678                 ecryptfs_printk(KERN_DEBUG, "Expanded file size to "
 679                                 "[0x%.16x]\n", i_size_read(inode));
 680         }
 681         ecryptfs_write_inode_size_to_header(lower_file, lower_inode, inode);
 682         lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
 683         mark_inode_dirty_sync(inode);
 684 out:
 685         kunmap(page); /* mapped in prior call (prepare_write) */
 686         if (rc < 0)
 687                 ClearPageUptodate(page);
 688         else
 689                 SetPageUptodate(page);
 690         mutex_unlock(&lower_inode->i_mutex);
 691         return rc;
 692 }
 693
 694 /**
 695  * write_zeros
 696  * @file: The ecryptfs file
 697  * @index: The index in which we are writing
 698  * @start: The position after the last block of data
 699  * @num_zeros: The number of zeros to write
 700  *
 701  * Write a specified number of zero's to a page.
 702  *
 703  * (start + num_zeros) must be less than or equal to PAGE_CACHE_SIZE
 704  */
 705 static
 706 int write_zeros(struct file *file, pgoff_t index, int start, int num_zeros)
 707 {
 708         int rc = 0;
 709         struct page *tmp_page;
 710
 711         tmp_page = ecryptfs_get1page(file, index);
 712         if (IS_ERR(tmp_page)) {
 713                 ecryptfs_printk(KERN_ERR, "Error getting page at index "
 714                                 "[0x%.16x]\n", index);
 715                 rc = PTR_ERR(tmp_page);
 716                 goto out;
 717         }
 718         kmap(tmp_page);
 719         rc = ecryptfs_prepare_write(file, tmp_page, start, start + num_zeros);
 720         if (rc) {
 721                 ecryptfs_printk(KERN_ERR, "Error preparing to write zero's "
 722                                 "to remainder of page at index [0x%.16x]\n",
 723                                 index);
 724                 kunmap(tmp_page);
 725                 page_cache_release(tmp_page);
 726                 goto out;
 727         }
 728         memset(((char *)page_address(tmp_page) + start), 0, num_zeros);
 729         rc = ecryptfs_commit_write(file, tmp_page, start, start + num_zeros);
 730         if (rc < 0) {
 731                 ecryptfs_printk(KERN_ERR, "Error attempting to write zero's "
 732                                 "to remainder of page at index [0x%.16x]\n",
 733                                 index);
 734                 kunmap(tmp_page);
 735                 page_cache_release(tmp_page);
 736                 goto out;
 737         }
 738         rc = 0;
 739         kunmap(tmp_page);
 740         page_cache_release(tmp_page);
 741 out:
 742         return rc;
 743 }
 744
 745 static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t block)
 746 {
 747         int rc = 0;
 748         struct inode *inode;
 749         struct inode *lower_inode;
 750
 751         inode = (struct inode *)mapping->host;
 752         lower_inode = ecryptfs_inode_to_lower(inode);
 753         if (lower_inode->i_mapping->a_ops->bmap)
 754                 rc = lower_inode->i_mapping->a_ops->bmap(lower_inode->i_mapping,
 755                                                          block);
 756         return rc;
 757 }
 758
 759 static void ecryptfs_sync_page(struct page *page)
 760 {
 761         struct inode *inode;
 762         struct inode *lower_inode;
 763         struct page *lower_page;
 764
 765         inode = page->mapping->host;
 766         lower_inode = ecryptfs_inode_to_lower(inode);
 767         /* NOTE: Recently swapped with grab_cache_page(), since
 768          * sync_page() just makes sure that pending I/O gets done. */
 769         lower_page = find_lock_page(lower_inode->i_mapping, page->index);
 770         if (!lower_page) {
 771                 ecryptfs_printk(KERN_DEBUG, "find_lock_page failed\n");
 772                 return;
 773         }
 774         lower_page->mapping->a_ops->sync_page(lower_page);
 775         ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n",
 776                         lower_page->index);
 777         unlock_page(lower_page);
 778         page_cache_release(lower_page);
 779 }
 780
 781 struct address_space_operations ecryptfs_aops = {
 782         .writepage = ecryptfs_writepage,
 783         .readpage = ecryptfs_readpage,
 784         .prepare_write = ecryptfs_prepare_write,
 785         .commit_write = ecryptfs_commit_write,
 786         .bmap = ecryptfs_bmap,
 787         .sync_page = ecryptfs_sync_page,
 788 };